As an answer to someone asking whether Unity will require a working OpenGL stack to operate in Ubuntu 11.04 "Natty Narwhal", Mark Shuttleworth announced that Canonical would offer an optional, QT-based, "2D" implementation of Unity. Here is a video, too.

I personally use Lubuntu, so this whole Unity debate feels irrelevant to me. However, when Ubuntu 11.04 finally comes out, I WILL give it a test drive if for no other reason than to see what all the angst is about. However, I'm more than likely to stick with Lubuntu thanks to it's fast performance and light memory requirements. I consider it the best of the *buntus.

But feel free to use whichever WM you like. That's one of the great things about Linux - we do have this kind of choice. Windows and OSX users are not so blessed.